Juvenile dermatomyositis (JDM), the most common pediatric inflammatory myopathy, is a systemic vasculopathy affecting young children. Epidemiology studies documenting an antecedent illness in the 3 mo before the first definite symptom (rash and/or weakness) of JDM are supported by immunologic data that suggest that the disease pathophysiology is Ag driven. The purpose of this study was to compare the gene expression profiles in muscle biopsies of four untreated DQA1*0501+ JDM children with profiles from children with a known necrotizing myopathy (Duchenne muscular dystrophy), as well as an in vitro antiviral model (NF90), and healthy pediatric controls. Nearly half (47%) of the dysregulated genes in JDM were associated with the immune response. In particular, increased expression of IFN-αβ-inducible genes 6-16, myxovirus resistance protein p78, latent cytosolic transcription factor, LMP2, and TAP1 was observed. This profile is consistent with an IFN-αβ transcription cascade seen in the in vitro viral resistance model. The IFN-αβ-inducible profile was superimposed on transcription profiles reflective of myofiber necrosis and regeneration shared with Duchenne muscular dystrophy. Expressed genes were confirmed by quantitative real-time PCR (6-16), immunofluorescence (thrombospondin 4), and immunolocalization (IFN-γ, p21). We hypothesize that these data support a model of Ag (?viral) induction of an apparent autoimmune disease based on dynamic interaction between the muscle, vascular, and immune systems in the genetically susceptible (DQA1*0501+) child.

Leflunomide, a novel immunosuppressive drug, is able to prevent and reverse allograft and xenograft rejection in rodents, dogs, and monkeys. It is also effective in the treatment of several rodent models of arthritis and autoimmune disease. In vitro studies indicate that leflunomide is capable of inhibiting anti-CD3- and interleukin-2 (IL-2)-stimulated T cell proliferation. However, the biochemical mechanism for the inhibitory activity of leflunomide has not been elucidated. In this study, we characterized the inhibitory effects of leflunomide on Src family (p56lck and p59fyn)-mediated protein tyrosine phosphorylation. Leflunomide was able to inhibit p59fyn and p56lck activity in in vitro tyrosine kinase assays. The IC50 values for p59fyn (immunoprecipitated from either Jurkat or CTLL-4 cell lysate) autophosphorylation and phosphorylation of the exogenous substrate, histone 2B, were 125-175 and 22-40 microM respectively, while the IC50 values for p56lck (immunoprecipitated from Jurkat cell lysates) autophosphorylation and phosphorylation of histone 2B were 160 and 65 microM respectively. We also demonstrated the ability of leflunomide to inhibit protein tyrosine phosphorylation induced by anti-CD3 monoclonal antibody in Jurkat cells. The IC50 values for total intracellular tyrosine phosphorylation ranged from 5 to 45 microM, with the IC50 values for the zeta chain and phospholipase C isoform gamma 1 being 35 and 44 microM respectively. Leflunomide also inhibited Ca2+ mobilization in Jurkat cells stimulated by anti-CD3 antibody but not in those stimulated by ionomycin. Distal events of anti-CD3 monoclonal antibody stimulation, namely, IL-2 production and IL-2 receptor expression on human T lymphocytes, were also inhibited by leflunomide. Finally, tyrosine phosphorylation in CTLL-4 cells stimulated by IL-2 was also inhibited by leflunomide. These data collectively demonstrate the ability of leflunomide to inhibit tyrosine kinase activity in vitro, and suggest that inhibition of tyrosine phosphorylation events may be the mechanism by which leflunomide functions as an immunosuppressive agent.

Ganglioside GM3 inhibits epidermal growth factor (EGF)-dependent cell proliferation in a variety of cell lines. Both in vitro and in vivo, this glycosphingolipid inhibits the kinase activity of the EGF receptor (EGFR). Furthermore, membrane preparations containing EGFR can bind to GM3-coated surfaces. These data suggest that GM3 may interact directly with the EGFR. In this study, the interaction of gangliosides with the extracellular domain (ECD) of the EGFR was investigated. The purified human recombinant ECD from insect cells bound directly to ganglioside GM3. The ganglioside interaction site appears to be distinct from the EGF-binding site. In agreement with previous reports on the effects of specific gangliosides on EGFR kinase activity, the ECD preferentially interacted with GM3. The order of relative binding of other gangliosides investigated was as follows: GM3 > > GM2, GD3, GM4 > GM1, GD1a, GD1b, GT1b, GD2, GQ1b > lactosylceramide. These data suggest that NeuAc-lactose is essential for binding and that any sugar substitution reduces binding. In agreement with the specificity of soluble ECD binding to gangliosides, GM3 specifically inhibited EGFR autophosphorylation. Identification of a ganglioside interaction site on the ECD of the EGFR is consistent with the hypothesis that endogenous GM3 may function as a direct modulator of EGFR activity.

Leflunomide has been shown to be very effective in preventing and curing several autoimmune animal diseases. Further, this agent is as effective as cyclosporin A in preventing the rejection of skin and kidney transplants in rats. Preliminary results from patients suffering from severe cases of rheumatoid arthritis demonstrated that clinical and immunological parameters could be improved with leflunomide therapy. Mode of action studies revealed that this substance antagonizes the proliferation inducing activity of several cytokines and is cytostatic for certain cell types. In this light, we could show that tyrosine phosphorylation of the RR-SRC peptide substrate and the autophosphorylation of the epidermal growth factor (EGF) receptor were, dose dependently, inhibited by leflunomide. EGF activates the intrinsic tyrosine kinase of its receptor, which stimulates the phosphorylation of a variety of peptides, the amino acid residue in all cases is tyrosine. These results indicate that much of leflunomide's activity could be due to the inhibition of tyrosine-kinase(s), which is an important general mechanism for the proliferation of various cell types. Thus, leflunomide, which is effective against autoimmune diseases and reactions leading to graft rejection, would seem to have a mode of action separating it from known immunosuppressive drugs.

2005. Fertilization, seeding date, and seeding rate for malting barley yield and quality in southern Alberta. Can. J. Plant Sci. 85: 603-614. Weather conditions are often unfavourable for malting barley quality in southern Alberta, but agronomic practice may improve the probability of attaining acceptable quality. The objective of this study was to determine optimum agronomic practice (cultivar, fertilization, seeding date and seeding rate) for yield and quality of malting barley in southern Alberta. Field trials were conducted at 12 dryland sites and 2 irrigated sites over a 3-yr period (2001)(2002)(2003). At each site, five experiments were conducted with the following treatments: (1) N rate (0, 40, 80, 120, and 160 kg N ha -1 ), (2) P rate (0, 6.5, 13 and 19.5 kg P ha -1 ), (3) K rate (0, 25 and 50 kg K ha -1 ), (4) S rate (0, 10, and 20 kg S ha -1 ), and (5) seeding date (three dates at 10-d intervals) and seeding rate (150, 200, 250, 300, and 350 viable seeds m -2 ). Seven cultivars were included in the first experiment and two cultivars were included in the remainder of the experiments. Maximum grain yields were achieved when fertilizer + available soil N (estimated from unfertilized grain N yield) exceeded 31 kg N Mg -1 maximum grain yield, whereas protein concentrations were usually acceptable if fertilizer + available soil N was between 25 and 40 kg N Mg -1 maximum grain yield. Higher N rates generally reduced kernel size. Cultivar differences in N response were negligible. Application of P, K, or S did not affect malt yield or quality. Seeding delays of ≈20 d reduced grain yields by an average of 20%, with relatively greater yield declines under drought stressed conditions. Delayed seeding did not affect or slightly increased grain protein concentration. Kernel size was both increased and decreased by delayed seeding. Increased seeding rates from 150 to 350 viable seeds m -2 generally provided small yield gains, slight reductions in grain protein concentration and reduced kernel size. The most beneficial agronomic practices for malt barley production in southern Alberta were early seeding and application of N fertilizer at rates appropriate to the expected availability of moisture and soil N. . La première expérience portait sur sept cultivars auxquels deux autres se sont rajoutés par la suite. Le rendement atteint un maximum quand le N de l'amendement plus le N disponible dans le sol (estimé d'après le rendement grainier sans fertilisation) dépassent 31 kg de N par mg de rendement grainier maximal, alors qu'on obtient une concentration en protéines généralement acceptable quand la somme des deux sources de N se situe entre 25 et 40 kg de N par mg de rendement grainier maximal. Une concentration d'azote plus élevée réduit habituellement la taille du grain. Les cultivars réagis-sent tous à peu près de la même façon à l'azote. L'application d'amendements P, K ou S ne modifie ni le rendement ni la qualité du grain pour la brasserie. Un retard de ≈ 20 jours dans les semis réduit le rendement grainier d'en...

in September 1992 to determine the effect of crop management on total, light fraction and mineralizable (10-wk) organic matter contents. Spring wheat was the dominant cropping system; treatments examined include fallow frequency, forage hay production in rotation, manure amendment, N fertilizer application, and native grass. The two latter treatments were infoduced in 1985 Total and light fraction organic matter did not vary among phases of the rotation whereas mineralized C tended to be lowest during and shortly after a fallow phase. When averaged across rotation phases, total, light fraction, and mineralized organic matter were enhanced by reduced fallow frequency, manure additons, hay production and native grass. Highest concentrations of total and labile organic concentrations in the 0-to 7.5-cm soil depth were generally found in the continuously-cropped wheat and native grass treatments. Hay production significantly increased soil organic matter in the 15-to 30-cm soil depth. Nitrogen fertilization did not increase soil organic matter in this study, likely because of minimal yield response over the treatment period.Sensitivity of the various indicators to treatment [ (highest-lowest)

Pax3 is a transcription factor that is

The formation of terminally differentiated plasma cells represents the critical final step in B-cell differentiation. In this study, utilizing oligonucleotide microarray analysis, we describe the highly specialized genetic profile exhibited by terminally dif-